1. Field of the Invention
This invention relates to a scanning probe microscope.
2. Description of the Prior Art
A surface condition of a substance can be investigated by a scanning probe microscope. In addition, atoms and molecules can be manipulated precisely in the order of nanometer dimension to atomic dimension. Therefore, the scanning probe microscope plays an important role in nano-technology.
With a conventional scanning probe microscope, however, only the aspect ratio of a surface of a substance or the like can be measured, but other physical properties of the substance, e.g., magnetic properties, can not be measured. The application of the scanning probe microscope is restricted, so can not be employed in a biochemical field.
It is an object of the present invention to provide a new scanning probe microscope which can measure and investigate various properties and can be applied for various fields, such as a biochemical field.
For achieving the above object, this invention relates to a scanning probe microscope comprising:
a cantilever,
a probe formed on the cantilever, and
a carbon nanotube having an armchair type crystal structure and electric conduction property which is formed at the forefront of the probe.
This invention also relates to a scanning probe microscope comprising:
a cantilever,
a probe formed on the cantilever, and
a carbon nanotube of which the forefront is chemically modified and substituted with modifying molecules and which is formed at the forefront of the probe.
In the scanning probe microscope of the present invention, a carbon nanotube is formed at the forefront of a probe made of a Si material or the like, so the resulting composite type probe is utilized as an actual probe. Since the diameter of the carbon nanotube is set within 0.4-50 nm, a minute structure of a substance can be measured and investigated with the scanning probe microscope.
In the first scanning probe microscope of the present invention, the carbon nanotube composing the probe has an armchair type crystal structure as shown in FIG. 1. Such a carbon nanotube tends to exhibit metallic properties, so comes to have electric conduction.
Therefore, if the quantum conduction of the carbon nanotube is utilized, physical properties of a substance can be measured and investigated precisely. The carbon nanotube may be connected with a spin-polarization electron beam source made of a ferromagnetic material, such as Fe, a super-conducting material, such as Al split in spin by a magnetic field of large strength, or a semi-conducting material, such as GaAs, which is optically excited. If the carbon nanotube is connected with the electron source, electrons are injected into a given magnetic substance and then, the tunnel current or the trajectory electron emission current from the magnetic substance is detected. In this case, the magnetic structure or the spatial distribution, such as spin polarization of the magnetic substance, can be investigated on the tunnel current and the trajectory electron emission current.
In the second scanning probe microscope of the present invention, the forefront of the carbon nanotube is modified by modifying molecules. Therefore, by selecting the kind and amount of modifying molecule appropriately, the resulting scanning probe microscope can be applied for various fields, such as a biochemical field.